The present invention relates to optical scanners and more specifically to a mirrored spinner with paired offset facets.
Typical bar code scanners use mirrored spinners to scan an incident laser beam into a series of ray fans. These fans, when projected onto a plane, produce a series of approximately straight curves (scan lines). Typically, the several facets of a mirrored spinner are inclined at different angles, so as to produce a set of spaced apart parallel lines. The length of these lines is proportional to the tangent of the facet scan angle and the distance between the spinner and the projection plane. Conventional spinners are regular polygons and produce sets of equal length scan lines.
In scanners incorporating conventional spinners for producing parallel horizontal scan lines for scanning vertically oriented bars and spaces and parallel vertical scan lines for scanning horizontally oriented bars and spaces, some of the vertical scan lines are redundant and wasted. The vertical lines fill the scan volume by their length, and do not require as much repetition.
Therefore, it would be desirable to provide a mirrored spinner with paired offset facets.